Abstract: Process and apparatus for dewatering slurry recovered from waste water, generated in the production and treatment of metals, are provided in which the flocculated slurry is first dewatered mechanically to provide a water output which is returned upstream for further treatment, and a sludge output containing about 25-32 percent by weight (w/o) solids and the remainder free liquid. The sludge is passed through a thermal drier and, after substantially all the free water has been removed, is disposed of as desired.